Pressure-fluid tool.



G. H. GILMAN.

PRESSURE FLUID'TOOL.

APPLICATION FILED DEC-21.1916. 1

1 36,703 Patented Aug. 14, 1917.

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GEORGE H. GILMAN, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR T0 SULLIVAN MACHINERY COMPANY, 015 BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

PRESSURE-FLUID TOOL.

Patented Aug. 14,1917.

Original application filed April 22, 1908, Serial No. 428,618. Divided and this application filed. December 21,

1916. Serial No. 138,187.

I '0 all whom it may concern.

Be it known that I, GEORGE H. GILMAN, a citizen of the United States, and a resident of Claremont, county of Sullivan, and State of New Hampshire, have invented an Improvement in Pressure-Fluid Tools, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

My invention relates to pressure fluid tools adapted to be operated by compressed air or other elastic pressure fluid, being more particularly concerned with the pro vision of simplified and eflicient Valve controlling means therefor. This application is a division of my prior copending application Serial No. 428,618, filed April 22, 1908.

My invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a longitudinal, central section taken through a pneumatic hammer embodying one form of my invention; and

Fig. 2 is a similar sectional view taken in a plane at right angles to the plane of the section shown in Fig. 1.

Referring to the drawings and to the embodiment of my invention illustrated therein, there is provided a cylinder 1, the rear or upper (Fig. 1) end of which has threaded engagement with a hollow casing 2, the latter having a closed end and acting as a housing for the rear end of the cylinder and a valve block 3. The cylinder is prevented from accidental unscrewing by a split clamping collar 4. A portion of a handle piece 5 or other member by which the tool is supported is shown, but it will be understood that the particular construction of handle forms no material part of this invention and that the same may be used with various handles or other supports well known in the art.

The valve block 3 has recessed into its lower or forward end a plate 6, the latter acting as a closure for the end of the cylinder and held in alinement with the valve block and cylinder for the necessary registration of the connecting passages by means of one or more dowel pins 7. The upper or rearmost end of the valve block rests against the walls of the casing 2 and is provided with an opening 8 afiording free communication between the valve chamber and a constant pressure chamber 9.

The valve is provided with two heads of different diameter, the one of larger diameter 10 and the one of smaller diameter 11 being separated by an exterior, annular valve groove 12. The smaller head 11 works in the rearmost portion of the valve chamher and has pressure constantly admitted to its end area through the passage 8, whereby such pressure constantly tends to press the valve forward.

During the forward movement of the piston the valve is held in the position shown in Fig. 2 by the pressure fluid acting against the constant pressure area at the rear end of the smaller head 11 until the piston nears the end of its stroke and the delivery of its blow upon the shank of a tool 13, the latter being held within a usual sleeve or bushing 14:.

Near the close of the forward movement of the piston the controlling valve is reversed by the admission of pressure fluid to the forward end area of the larger head 10, which fluid acting against the larger pressure area of the valve at that end acts to reverse the valve against the constant pressure upon the smaller pressure area provided by the smaller head 11.

The larger head 10 works in the foremost and enlarged portion of the valve chamber and has pressure fluid alternately admitted to and exhausted from its end pressure area through an intermittent pressure passage 15, which opens into the valve chamber through a radial or lateral passage 16 and into the cylinder through a port 17 and also through a second and more advanced port 18.

The intermittent pressure passage 15 is placed in communication with a constant pressure passage 19, which latter opens into the cylinder through a port 20 by means of a circumferential groove 21 formed in the piston. When the circumferential groove uncovers the ports 20 and 17 pressure fluid is admitted to the lower or forward end of the valve chamber to raise the valve. The

constant pressure passage 19 connects with the passage 8 by means of a lateral passage 22 so that pressure fluid is constantly admitted to the passage 19. r

The rear, contracted portion of the valve chamber is provided with an annular groove 23 connected with the rear end of the cyl inder by means of one or more longitudinal passages 24. When the valve is depressed in its forward position as represented in Fig. 2', the end edge or area of the smaller head 11 uncovers the said groove 23 to the live pressure, thus admit-ting pressure fluid to the rear end of the cylinder and driving the piston forward.

The valve block is provided with one or more radial exhaust passages 25 opening into an annular exhaust space 26 and in constant communication with the space surrounding the annular valve groove 12. In

the forward position of the valve (Fig. 2)

a return passage 27 leading to the forward end of the cylinder through a port 28 is placed in communication with the said exhaust passage 25 through such annular groove, so that pressure fluid is exhausted from the forward end of the cylinder. When the valve is reversed by admission of pressure fluid from the constant pressure passage 19 to the intermittent pressure passage 15 about the contracted groove portion 21 of the piston, the valve is returned to the position shown in Fig. 1 wherein pressure fluid is exhausted from the rear end of the cylinder through the longitudinal passage or passages 24 and the valve chamher groove 23, which latter is now placed in communication with the exhaust passages 25 by the annular groove 12. At the same time pressure fluid is admitted tothe forward end of the cylinder to return the piston through the return pressure passage 27 The latter communicates with the valve chamber throiigh a radial passage 29, which latter is caused to communicate with pressure fluid conducted thereto through the interior of the valve. The smaller head of the valve is open to the pressure fluid re ceived through the passage 8 and the valve is provided with one or more radial ports 30 opening from the interior of the valve outwardly through the larger head. In the forward position of the valve represented in Fig. 2, these ports are closed to pressure fluid by means of a stationary plug 81 which projects rearwardly from the plate 6 into the hollow interior of the valve, thereby closing the lower end of the valve and at the same time preventing access of pressure fluid to the interior surface of the valve at its forward end.

When the valve is returned to the posi tion shown in Fig. 1, the radial ports 30 are opened to the pressure fluid within the valve and at the same time placed in free communication with the lateral port 29 by any suitable means, such, for example, as an exterior, annular groove 32, although, as will be obvious, the'g'roove 32 be formed in the valve chamber in registration with the port 29 instead of in the valve.

It therefore follows that during the forward movement of the piston the mlve is in the position shown in Fig. 2 and pressure fluid is admitted to the rear end of the cylinder through the circumferential groove 23 ar d longitudinal passages- 24 and exhausted from the forward end of the cylinder through the passage 27, port 29, circumferential groove 12 and exhaust passage 25.

On rearward movement of the piston following the reversal of the valve to the position shown in Fig. 1, pressure fluid is admitted to the forward end of the cylinder through the interior of the valve, the radial ports 80, the port 29, and passage 27, and is exhausted from the rear end of the cylinder through the longitudinal passages 2a,

the annular groove 13 and the exhaust pas sages 25. v

The piston has a reduced portion 33 hav ing sliding fit within contracted walls 34: of the cylinder, the effective area against which the pressure fluid acts in returning the piston being that providedby the shoulder formed between the contracted portion and the main body portion of the piston. lVhen the return piston movement has proceeded far enough to withdraw the reduced piston portion from the contracted cylinder walls 34;, the forward end ofthe cylinder is placed in communication with a tool space 35, the latter being in free communication with the atmosphere through an exhaust port 30:

It will be evident that on the rearward stroke of the piston, the valve is again moved from the positionshown in Fig. 1 'to" that shownin Fig. 2,- when the second or more advanced port 18 connected with the inter mittent pressure passage 15 is iincovered by the piston and opened to theexhaustopening 36, this resulting in exhausting the pressure fluid fromthe larger area at the front of the valve chamber, and causing the pres sure'qfluid at the rear end of the valve to by an exterior annular groove, the end of the smaller head being constantly exposed to pressure fluid supply and having means for admitting pressure fluid to the interior of the valve, the end of the larger head being closed by a fixed, central plug on Which the valve is adapted to slide, said end being intermittently exposed to pressure fluid through movement of the piston, a port connected With the rear end of the cylinder and adapted to be intermittently opened to the pressure fluid by the smaller head, and a port connected to the forward end of the cylinder and adapted to be intermittently opened to the interior of the valve.

2. A pressure fluid tool having a cylinder, a piston, a differential, pressure actuated, hollow, tubular valve, the latter having two heads of difierent diameter separated by an exterior annular groove, the smaller head being constantly exposed to pressure fluid to move the same in one di- Gopies of this patent may be obtained for rection and the larger head being intermittently exposed to pressure fluid to move the same in the opposite direction, one or more passages opening laterally from the hollow interior of the valve through the enlarged head thereof, a stationary member upon Which the valve is adapted to slide, said member entering the open end of the enlarged head and preventing communication between the interior of the valve and the larger pressure area at the end thereof, means to utilize the smaller head of said valve to place one end of said cylinder inter mittently in communication With the pressure fluid supply, and means to utilize said passage or passages in the larger head of said valve to place the other end of said cylinder in communication With the pressure fluid supply.

In testimony whereof, I have signed my name to this specification.

GEORGE H. GILMAN.

five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

